<The premise here at Princeton is sequestration is easier from big plants, so use hydrogen for mobile sources.>
Okay, so we could:
Strip hydrogen from water [by photovoltaic-driven electrolysis], deliver the H2 to vehicles and the O2 to carbon-burning power stations, which will send their exhaust into liquefaction and sequestration systems.
There'll be a lot of it and power stations need cooling so lakes under the ocean seem a good idea. The CO2 could be dragged back up [1.2 Specific gravity so hard work from 400 metres, but not all that bad] if needed to avoid an ice-age by release into the atmosphere to keep us warm.
Oh, hang on, very easy to get back up! Just like a geyser. Use the heat of the ocean to vapourize it once it gets to less than 400 metres down and it'll come roaring out and the energy of gasification could be used to generate a lot of power via a gas turbine at the surface. Yeah! That would be a lot of fun.
Heck, with the pressure off at the top, it'd blow out in a huge hurry if enough heat could get through the pipe. If it couldn't get enough heat, the ocean around the pipe would freeze as the heat was absorbed by the boiling CO2 zooming up the pipe and liquid CO2 would come squirting into the atmosphere.
Okay, cancel the gas turbine and go to a Pelton wheel turbine.
Some serious cooling capacity would be available at the surface if liquid CO2 was gushing out.
Oh, no! Cancel that thought! The 1.2 SG of CO2 would mean that the gaseous CO2 flow rate would reduce as the pipe froze up so there would be a column of very cold liquid up to about 80m from the surface [20% of the way to 400 metres where CO2 gas at ambient temperatures turns liquid] with very cold gas above that with boiling depending on how thick the ice was around the pipe.
Ooops, no, hang on. Ocean SG is about 1.1, so the CO2 liquid would come right up to about 40 metres.
Anyway, you can do the boe calculations.
Heat transfer fins around the pipe would help the rate of evaporation in the pipe and avoid freezing up.
For vehicles, it seems to me that clean-burning C4 to C8 liquids would be the best way to go. Emissions from those could be super low and avoid the high capital cost and drama of fuel-cells and other exotic energy systems.
Check around the city and you'll find that clean-burning modern petrol [gasoline in American for yous Yanks] engines are NOT the problem. Diesel engines remain the main problem. Crusty old cars on aromatic fuels are not much good either.
A little Ka using an Orbital engine on C4-C8 aliphatic fuels will be nice to stand behind. No need for fancy new expensive stuff.
Mqurice
PS: For non-science people, boe = back of envelope
Actually, on a bit more reflection, I suppose the column of CO2 would pulse as the heat flows vary as fresh CO2 is pushed up from the reservoir, heating the pipe from the inside, causing the cold column above the fresh, warmer CO2 liquid to be blown out in a big hurry in a geyser effect.
It could make Old Faithful look pathetic! |
